Horst played college soccer at Old Dominion University, and in the USL Premier Development League with Reading Rage, Virginia Beach Submariners and the Hampton Roads Piranhas.

[1] Horst played four years at Old Dominion University, leading the Monarchs to back-to-back Sweet 16 appearances in the NCAA Men's College Cup.

Horst was recipient of the Norfolk Sports Club's Tom Scott award as ODU's top senior student athlete.

The Puerto Rico Islanders won the USSF Division 2 Professional League Championship on October 30, 2010, against the Carolina Railhawks.

On December 5, 2018, Horst retired from professional soccer, with his contract option for the next season declined by the team due to circumstances around his age and injury history.